The high-precision cold drawn tube has good mechanical properties and excellent economic and technical value when it is used. The cylinders used in many countries are manufactured by high-precision cold drawn tubes. Pay attention to the following points when rolling high-precision cold drawn tubes.
1. Whether the rolling pressure is selected correctly or not, it has an effect on the surface roughness, size and precision after rolling. Generally, the rolling pressure is increased and the surface roughness is increased.
2. Improve the surface roughness of the workpiece, and the rolling effect is better. When the pre-machining roughness reaches Ra1.6, the roughness can reach Ra0.2 or more as long as the interference is suitable. However, when the pre-machining roughness is only Ra6.4 to Ra3.2, and the machined surface has vibration and knives, the deeper stencil cannot be rolled, and only the increased interference is rolled again.
3. The material is soft, plastic, and easy to be rolled. As the plasticity decreases, the hardness increases and the amount of deformation decreases. Generally, the rolling effect of steel and copper is better, and the effect of cast iron is poor. Wrought iron, ductile iron has better rolling effect than gray cast iron.
4. Rolling tools usually have balls, cylindrical rollers, conical rollers, rollers, and the like. However, the use of balls as deforming members reduces the cost of the entire rolling tool. Moreover, the ball has high precision, high hardness, and small contact surface with the workpiece. With a small rolling pressure, a small interference can obtain a higher pressure and a smaller roughness. Moreover, the balls are used for a long time, are not easy to wear, are inexpensive, and are easy to replace.